Los Angeles. The war's over, the GIs are home, Truman's in the White House and the mobsters are making a killing — as usual.

Into the office of a private investigator walks a mysterious little man with a story that's out of this world. He says he's lost his memory. He wants the PI to help him. When he turns out his pockets, he produces a pile of bizarre objects, each of which restores a memory and solves a part of the puzzle.

And the memories seem to belong to seven different people.

Decalog is a new concept in Doctor Who fiction: a cycle of ten linked stories.